Avalanche Modeling Project
The objective of this activity is to build a model of an avalanche using two
variables, terrain (rocky vs. smooth) and slope for a snowpack that you will design.
You will complete this project in groups.
Part
Part
Part
Part
Part
I:
II:
III:
IV:
V:
Snow Crystal Analysis
Build your Terrain
Changing the Slope
Snowpack Design
Conducting your Experiment
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Part I: Snow Crystal Analysis
In order to simulate an avalanche, you must understand the size and shape
characteristics of the substances you use to represent different types of snow.
Knowing these characteristics can help you identify strong and weak layers in a
snowpack.
Follow the steps below to analyze one of the substances that we will use to
represent snow. You will share your results with the rest of the class.
1. Each group will analyze one of five substances: flour, sugar, borax, potato
flakes, or Epsom salt. Make a slide of your substance and take it to the
digital microscope. (If another group is already working on the digital
microscope, move on to Part II: Build Your Terrain, and come back to this
analysis when the digital microscope is free).
2. Place your slide on the stage of the digital microscope. Focus the
microscope on your crystals. Pick out an average-sized crystal to measure
for your analysis.
3. Click on the camera icon on the computer screen and then click on the
“Snapshot” button to take a picture of your crystal. Once the picture is
taken, click on the thumbnail-sized version and click on the “Transfer”
button. Your picture should fill the background on the computer screen.
Print out a copy of your picture and sketch or trace the picture into the
“Sketch” section of the Snow Crystal Summary table on page 4 for your
substance.
4. Now you will take a measurement of your crystal. Make sure that the
Capture Control window reads “Measure Mode On.” Then, click on the
“Measure…” button at the bottom of the screen. Measure your crystal using
the unit called microns (mm, thousandths of a millimeter). Use your mouse to
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do the measurement. The cursor turns to a crosshair (+). Center the
crosshair on one side of your crystal and click once. Move your cursor to the
opposite side of the crystal and click once again on the edge. The diameter
measurement will appear on the screen. Measure your crystal’s diameter in
3 different places, write them below, and calculate the average diameter.
(Note: if your crystal is more rectangular, measure length and width and
take the average of the two measurements)
Diameter #1
Diameter #2
Diameter #3
Average Diameter =
Write the average diameter of your substance in the “Crystal Size” section
of your table.
5. Now find the snow classification that is closest to your crystal. Go to the
next computer and look at the snow classification sheet on the screen. Pick
out the shape that looks most like your crystal and write the name in the
“Snow Classification” section of your table.
6. Share your findings with the class and complete your table with information
from other groups.
7. In the “Rank size” category of the table, rank order the crystal types from
smallest to largest (1 = smallest, 5 = largest)
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Avalanche Model
Snow Crystal Summary
Substance
Sketch
Crystal Size
flour
sugar
borax
potato flakes
epsom salt
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Snow Classification
Rank size
Part II: Build your terrain
In this part of the lab, you will build your avalanche terrain on a whiteboard
that will be covered in butcher paper. You will use the butcher paper to separate
the terrain into two 6” wide avalanche chutes, one smooth and the other rocky.
Use the diagram below as a guide.
Use tape to attach the paper to the board.
When your chutes are ready, glue sand & rocks to one chute.
Leave the other chute plain.
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Part III: Changing the slope
In this part of the lab, you are building a mechanism for changing the slope
of your avalanche terrain. You will need the following materials:
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Completed terrain board
Ring stand (with ring)
String
2 Large rocks
Protractor
Use the diagram below as a guide.
1. Tie the string securely through the handle of the white board.
2. Lay the board flat on the table right in front of the ring stand, with the
handle side closest to the ring stand.
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3. Loop string around the ring on the ring stand. Leave at least 12” and tie a
loop at the end. You should be able to increase the slope of your terrain
easily by pulling the string.
4. Secure the base of your slope by placing large rocks at the end of the slope
to prevent your terrain board from moving.
5. Attach a protractor to the table at the end of the terrain board as shown.
Measure the maximum angle (in degrees) to which you can move your slope
(your minimum slope is zero, of course). It should measure at least 35º.
6. Test your mechanism to be sure that it works well before adding your
snowpack.
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Part IV: Snowpack Design
Now that you have information about your snow substances, you will define
the layers in your snowpack for the avalanche experiment. Each layer in your
snowpack represents a different snowstorm with different snow characteristics.
Choose 4 layers for your snowpack. You have 5 materials to choose from, and you
need to use at least 2 different materials. Remember that the more denselypacked the crystals can become, the more stable the layer will be. So, smaller
crystals should be more stable than larger crystals. Shape can also affect density
and stability.
Refer to the table you completed about the characteristics of your “snow”
and design a snowpack. Label the layers for your snowpack in the diagram below.
**Try to make the most stable snowpack possible!
top
bottom
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On your avalanche terrain whiteboard, build your snowpack just below the handle.
Use the snowpack you just designed as a guide, starting with the bottom layer and
working your way up.
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Part V: Conducting your experiment
You will answer several questions to describe what happened in your
experiment. You will conduct your experiment ONCE, so it’s very important to read
through the questions beforehand so you know what information to collect. Answer
the following questions about your avalanche experiment:
1. What was the slope angle of your avalanche?
2. Which terrain avalanched first, rocky terrain or smooth terrain? Or did
they both avalanche at the same time?
3. Which parts of the snowpack avalanched?
a. Did the entire snowpack avalanche at once?
b. Did only certain layers slide? If so, which ones?
4. Which layer was the weak link?
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a. What crystal substance was it?
b. What was the size rank of the weakest crystal (refer to your Snow
Crystal summary table)?
c. Did crystal size matter? Was it smaller or larger than the other
crystals in your snowpack layers?
d. What was the general shape of the weakest crystal?
e. Did crystal shape matter? How did the shape of the crystals in the
weak layer compare to crystals in the other snowpack layers?
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5. If you could change anything in your experiment to make the situation as
stable as possible (in other words, no avalanche!), what would you change?
a. Terrain?
b. Snowpack layers?
Keeping these questions in mind, conduct your experiment.
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Raise the board slowly
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STOP as soon as the snow starts to slide down the board
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Hold the board in that spot while you can gather the information you
need for your summary.
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